Colon Cancer

By staff

US Pharm. 2018;43(12):11-12.

Third-Leading Type of Cancer in the U.S.

Colon cancer, also referred to as colorectal cancer, is cancer that affects the colon or rectum in the large intestine. These two types of cancers are often grouped because they have many features in common, including symptoms and treatment. Colorectal cancer is the third-leading form of cancer diagnosed in both men and women. As many as 97,000 cases of colon cancer and 43,000 cases of rectal cancer are diagnosed each year in the United States. Colon cancer occurs in all racial and ethnic groups and is most often diagnosed in those over the age of 50 years. Rates of colorectal cancer in those younger than age 50 years, however, are increasing.

Begins With Polyps in the Intestine

Colon and rectal cancers often begin with the formation of a polyp, an abnormal clump of cells in the lining of the colon or the rectum, which can become cancerous if it is not removed. Anyone can develop colorectal polyps, but those who are age 50 years or older, are overweight, smoke, or have a personal or family history of colon polyps or colon cancer are at the highest risk. Diet plays a significant role in the risk of developing colorectal cancer. The standard American diet is generally high in fat and low in fiber, which may negatively influence the microbes that usually live in the colon. Much research is underway to better understand the importance of the gut biome on the risk of colorectal and other types of cancer and chronic health conditions.

Preventable and Curable if Found Early

Since polyps and early stages of colorectal cancer do not cause noticeable symptoms, regular screening is recommended for individuals between the ages of 50 and 75 years. Some individuals should start screening before age 50 years if they have a close relative with colorectal polyps or colon cancer, have an inflammatory bowel disease such as Crohn’s disease or ulcerative colitis, or have specific genetic syndromes.

There are several options for colorectal cancer screening, but colonoscopy is the gold standard and is always done when there is a strong suspicion that cancer or polyps exist. During a colonoscopy, an endoscope (a flexible tube with a camera on its tip) is inserted into the rectum and moved through the length of the colon. If polyps or suspicious tissue is seen during the colonoscopy, the physician will collect a small piece of tissue and send it out for testing. This is called a biopsy and is used to diagnose cancer, infection, or general inflammation.

Less invasive options exist for some patients who do not want to undergo colonoscopy. Stool DNA testing is an option for those with an average risk profile and no personal history of polyps or colorectal cancer. For this noninvasive test, patients use an at-home kit to collect a stool sample that is mailed to a laboratory for testing. The laboratory looks for specific changes to the DNA that could be signs of cancer or precancerous growths. Another minimally invasive option for colorectal cancer screening is the CT colonography, or virtual colonoscopy, in which a CT scan produces an image of the colon. If either the stool DNA testing or the virtual colonoscopy detects changes, the patient will undergo a full colonoscopy and biopsy.

Treatment Depends on Cancer Stage

If tests reveal that colorectal cancer is present, the physician will determine the extent (stage) of cancer. The stages range from Stage 1—where the cancerous tissue has stayed within the lining of the rectum or the colon and has not spread outside of the large intestine—to Stage 4, where cancer has spread to sites in the body outside of the digestive tract, such as other organs like the liver. Doctors will recommend treatment based on the stage of colorectal cancer. Surgery, radiation, and chemotherapy are the three primary treatment options.

If you have questions about colorectal cancer–screening options, or about cancer treatment, be sure to ask your pharmacist or another trusted healthcare practitioner.